Underwater wellhead connector



June 23, 1970 E w. H. PETERSEN 3,516,492

UNDERWATER WELLHEAD CONNECTOR Filed May 23, 1968 v 2 Sheets-Sheet 1 Y/V/Y INVENTOR:

WILLIAM H. PETERSEN aw 4 v HIS ATTORNEY Jun 3, 1970 w. E. PETERSEN3,516,492

UNDERWATER WELLHEAD CONNECTOR Filed May 23. 1968 2 Sheets-Sheet 2 nfil55 K 5? WI 67 ll n ll FIG. 2

INVENTOR WILLIAM H. PETERSEN HIS ATTORNEY United States Patent 3,516,492UNDERWATER WELLHEAD CONNECTOR William H. Petersen, Houston, Tex.,assignor to Shell Oil Company, New York, N.Y., a corporation of DelawareFiled May 23, 1968, Ser. No. 731,381 Int. Cl. E21b 43/ 0] F161 39/00 US.Cl. 166-.6 4 Claims ABSTRACT OF THE DISCLOSURE The present inventionrelates to oil well equipment for use at underwater locations. Moreparticularly, the invention relates to a wellhead connector which may beused to establish operative communication between a vessel floating onthe surface of a body of water and a wellhead assembly or productioncontrol unit of an underwater well whereby maintenance or otheroperations with respect to the well and/or wellhead assembly may becarried out from the vessel.

A recent development in the field of oil well drilling is the completionof wells at offshore locations with a wellhead assembly positioned on orclose to the ocean floor out of the way of ships which might otherwisedamage it in the event of collision. Equipment placed on the oceanfloor, however, is exposed to conditions such as the corrosive nature ofthe sea water and the presence of marine life which tends to grow andbecome encrusted on metallic structures below the surface of the water.

It is necessary therefore from time to time to go back into a wellwherever it has been completed for well servicing or work-overoperations. In addition, the underwater wellhead assembly itself maycall for periodic repair and maintenance. Accordingly, it is desirableto have an underwater wellhead assembly of suitable design so that itmay be readily removed from the underwater wellhead and raised to thesurface. It is also desirable to have a wellhead assembly of aconstruction which will permit work-over operations in the well from thevessel through the assembly. One underwater wellhead assembly permittingboth of these operations as desired is disclosed in US. Pat. No.3,064,734, issued Nov. 20, 1962, to R. J. Bauer et al.

In accordance with present practice, maintenance or other underseaoperations with respect to a producing well are usually initiated byestablishing guide means, such as guidelines, between the vessel and thewell site. A suitable wellhead connector device is then normally loweredby means of a pipe string along the guide means to the wellhead assemblywhereupon the desired operations are performed from the vessel. Someoperations may be performed with the wellhead assembly remaining inplace but occasionally it may be necessary to disconnect the wellheadassembly from the underwater wellhead and production flow lines and pullit up to the vessel by means of the pipe string along the guide means.

Time is an important consideration in offshore oil well operations dueto the large per diem expenses involved in the rental of bargeequipment, wages, etc. Then too,

3,516,492 Patented June 23,, 1970 prolonged well shut-down formaintenance is costly due to lost oil production. Accordingly, it isadvantageous to perform all operations relating to an undersea well,including maintenance and work-over operations, as quickly as possible.

SUMMARY OF THE INVENTION It is therefore a primary object of the presentinvention to provide a wellhead connector which can be lowered from afloating vessel and positioned on an underwater wellhead assemblywithout the necessity of first establishing guide means between thevessel and the wellhead site.

A further object of the present invention is to provide a wellheadconnector incorporating wellhead assembly locating and positioning meansfor assisting the operator in locating the wellhead assembly andoperatively positioning the connector with respect to the wellheadassembly.

These objects have been attained in the present invention by providing awellhead connector lowerable from a floating vessel which incorporatessonar and TV equipment for assisting in the positioning thereof on anunderwater wellhead assembly. After the connector is locked intoengagement with the assembly by suitable latch means, an inner conduitassembly incorporated in the wellhead connector is moved by prime movermeans into operative association with production tubing extending intothe well. Since the inner conduit assembly is also in continuous fluidcommunication with one or more tubing strings extending to the vessel,desired operations may be carried out from the vessel with respect tothe well and/ or wellhead assembly.

DESCRIPTION OF THE DRAWING These and other objects of this inventionwill be understood from the following description taken with referenceto the drawings wherein:

FIG. 1 is a diagrammatic view illustrating a barge or vessel floating onthe surface of a body of water over an underwater wellhead assembly, thevessel having depending therefrom the wellhead connector according tothe present invention;

FIG. 2 is a longitudinal view taken in partial crosssection illustratingthe wellhead connector according to the present invention in operativeengagement with an underwater wellhead assembly; and

FIG. 3 is an enlarged, partial cross-sectional view illustrating aportion of the wellhead connector according to the present invention inassociation with a cooperating portion of an underwater wellheadassembly.

Referring to FIG. 1 of the drawing, a drilling vessel or barge 11 of anysuitable floatable type is illustrated as floating on the surface of abody of water 12 and substantially fixedly positioned over a preselectedlocation by suitable barge positioning means or by being anchored to theocean floor 13 by suitable anchors (not shown) connected to anchor lines14 and 15. Equipment of this type may be used when carrying onoperations in water depths varying from about to 1500 feet or more. Thedrilling barge is equipped with a suitable derrick 16 as well as otherauxiliary equipment needed during well work-over or maintenanceoperations. The derrick 16 is positioned over a drilling slot 17 whichextends vertically through the barge in a conventional manner. Whenusing the equipment according to the present invention, the slot ofvessel 11 may be either centrally located or extend in from one edgethereof. However, operations may be carried out over the side of thebarge or vessel without the use of a slot.

' An underwater wellhead structure is illustrated in FIG. 1 ascomprising a base member 18 which is positioned on the ocean floor 13and is fixedly secured to a large diameter well casing 19 which extendsdown into a well, which has been previously drilled, and is preferablycemented therein. One or more strings of production tubing such astubing strings 20 and 21 are suspended within the well casing and extendinto the well in the usual manner. If desired, the wellhead structuremay include two or more vertical guide columns 22 and 23 adapted tocooperate with guide lines extending downwardly from vessel 11 in themanner which is more clearly set forth in copending US. patentapplication Ser. No. 731,382, filed May 23, 1968.

Positioned on base member 18 is a casinghead unit 24 with a wellheadassembly or production control unit 25 attached thereto. Normally, theproduction control unit or wellhead assembly is in fluid communicationwith the production tubing and comprises the necessary piping, valves,chokes, and other equipment normally connected together and mounted onthe top of a well, and known as a Christmas tree, together with thenecessary hydraulic or electrical systems, including pumps, reservoirs,motors, etc., to operate the valves at the head of the well from aremote location. A typical example of a suitable underwater productioncontrol unit or wellhead assembly for use at an offshore well location,and its manner of operation, is shown and described in U.S. Pat. No.3,064,- 735, issued Nov. 20, 1962, to R. J. Bauer et al. For purposes ofillustration, it will be assumed that the wellhead assembly utilized inconjunction with the present invention will be similar to that describedin the above patent, although it is of course obvious that the wellheadconnector according to the present invention could be used with othersuitable wellhead assembly designs.

Wellhead 25 includes one or more fluid flow handling conduits, such asconduits 26 and 27, and an upstanding wellhead entry conduit 28. Fluidflow handling conduits 26 and 27 communicate with production tubingstrings 20 and 21, respectively, and are smoothly curved in an are whichwould permit objects, such as through-the-flowline tools to becirculated therethrough into the well.

Depending from drilling platform 11 by means of a pipe string 29 is thewellhead connector 30 according to the present invention. If desired,connector 30 may have operatively associated therewith guidelinecarrying means 31 and 32 and guidelines 33 and 34 depending from Vessel11. It is to be understood that upon the eventual lowering of guidelinecarrying means 31 and 32 into communication with guide columns 22 and 23the guidelines would be connected thereto in some suitable manner.However, columns 22 and 23, guide line carrying means 31 and 32, andguidelines 33 and 34, form no part of the present invention and areshown here for purposes of illustration only. The wellhead connector 30could be suitably used without a guideline arrangement if desired.

Referring now to FIG. 2, wellhead connector 30 includes a cylindricalbody member 35 defining a throughbore 36 into which extends tubing runs37 and 38. Tubing runs 37 and 38 extend upwardly within pipe string 29to vessel 11. Preferably, the tubing runs 37 and 38 are each comprisedof individual tubing sections of substantially the same length as thesections of pipe comprising pipe string 29 and are integrally attachedthereto by suitable internal frame means to form integral units. Anarrangement of this type is disclosed in copending US. application No.690,996, filed Dec. 15, 1967. However, the tubing runs may beindependently disposedwithin pipe string 29 if so desired.

A framework 39 is attached to the lower end of body member 35 andextends outwardly therefrom in the manner shown. The framework 39carries wellhead assembly locating means and positioning means forassisting the operator on vessel 11 in locating wellhead assembly 25 andoperatively positioning connector 30 thereon. These operations will beexplained in more detail below. It should be noted at this point,however, that the locating and positioning means illustrated include ahydraulically A, actuated, extensible sonar unit 40 and a televisioncamera 41 both of which may be utilized to monitor operations at thewell site. A lamp unit 42 is affixed to television camera 41 to providesufficient illumination during the course of the underwater operations.The camera 41 may be fixedly mounted but it is preferred that it bemovably mounted for positioning at the will of the operator to providegreater flexibility with respect to what may be observed during thecourse of operations. Since television cameras and sonar units used forthe purpose described are familitar to those skilled in the art and areset forth in patent and other literature, a detailed description of theoperation thereof is not believed necessary. Also attached to the lowerend of body portion 34 is a downwardly extending cone-shaped element 43having a cutout portion 44 which is positioned to permit the camera toview operations taking place within the confines of the cone-shapedelement 43. Cone-shaped element 43 also assists in the positioning ofconnector 30 onto the well head assembly as described below.

Body member 35 includes an inner cylindrically-shaped body memberportion 45 which is mounted for downwardly extensible axial movementwith respect to the rest of the body member. The body member portion 45is normally biased by any suitable means, such as spring means (notshown), into a retracted first position. A flange member 46 is anintegral part of body member portion 45 and a resilient O-ring member 47is accom modated thereby which sealingly engages inner wall 48 of bodymember 35 thereby defining chamber 49 which is the annular space betweenbody member portion 45 and the remainder of body member 35. A pluralityof accumulators 50 are fixedly disposed about body member 35 and areattached thereto by any desired means. Conduits 51 provide fluidcommunication between accumulators 50 and chamber 49 with suitable valvemeans (not shown) being disposed within conduits 51 to establish orbreak the fluid communication between the accumulators 50 and chamber 49as desired. The actuation of these valves Would be accomplished remotelyfrom vessel 11 in the well-known manner. In the illustrated embodimentof the invention cable 52 including a plurality of electrical and/ orhydraulic conduits 53 is shown for conducting energy pulses from vessel11 to the various valves, latches, etc. employed in wellheadconnector'30. Valves referred to herein may be either electrically,pneumati cally or hydraulically actuated as desired.

The operation of the wellhead connector according to the presentinvention will now be described with greater particularity. It will beassumed that vessel 11 has been positioned over the approximate locationof the wellhead assembly 25 upon which the desired operations are to beperformed. The most usual method for accomplishing this is by surveyingin on the known site of the well by suitable instruments aboard thevessel. As soon as the well location has been surveyed in and the vesselsuitably positioned by anchor or other means, wellhead connector 30 isattached to pipe string 29 by any known coupling means and lowered fromthe vessel by adding additional sections of pipe to the string in thecustomary manner. This operation continues until it is determined thatsufficient pipe sections have been added to position the connector at adistance from the ocean floor 13 somewhat greater than the height ofwellhead assembly 25.

At this point the sonar unit 40 and the television camera 41 (as well aslight 42) are actuated and monitored from vessel 11. The pipe string 29and wellhead connector 30 are then manipulated from the vessel toposition them in axial alignment with wellhead entry conduit 28.Additional pipe sections are then connected to the top of the pipestring 29 to lower connector 30 into engagement with wellhead entryconduit 28. The cone-shaped element 43 will act to axially alignconnector 30 with respect to conduit 28 as it is lowered thereon andtelevision camera 41 with its unobstructed view through cut-out portion44 will permit the operator on vessel 11 to view the operation. Thelowering of connector 30 over wellhead entry conduit 28 continues untilthe top of conduit 28 firmly seats against the bottom of stop means 54which comprises a shoulder section of the body member wall and extendsinto chamber 49 as shown in FIG. 2.

As may also be seen with reference to FIG. 2, an annular groove 55 isformed about the periphery of wellhead entry conduit 28. Upon theseating of the top of conduit 28 against stop means 54, hydraulicallyoperated latch members 56 and 57, which are associated with suitablehousings attached to body member 35, are actuated and positionthemselves in groove 55 in the manner shown. It is, of course, obviousthat suitable conventional hydraulic lines and hydraulic pressure sourcemeans are provided to actuate the latch members, but these elements havenot been shown for purposes of clarity. The latch members 56 and 57 maybe actuated either automatically upon the seating of the conduit 28against stop means 54 or by an operator on vessel 11. Latch lockingmeans 8 and 59, also hydraulically operated, are actuated after latchmembers 56 and 57 are in operative association with groove 55. Latchlocking means 58 and 59, also hydraulically operated, are actuated afterlatch members 56 and 57 are in operative association with groove 55.Latch locking means 58 and 59 serve to lock the latch members 56 and 57into engagement with groove 55 in the manner shown in FIG. 2. Onceagain, for the purpose of clarity, the complete hydraulic system foroperating latch locking means 58 and 59 has not been shown. If desired,the latch locking means may be actuated at the will of an operator onvessel 11 or automatically upon the positioning of latch members 56 and57 in groove 55.

Referring now to FIG. 3, the respective relative positions of bodymember portion 45 and wellhead entry conduit 28 are shown just after theabove-described latching operation has been completed. Body memberportion 45 is in its retracted first position. It is also assumed thatwellhead connector 30 has been properly rotatably aligned with respectto entry conduit 28 to the position illustrated. This may be done eitherby manipulating pipe string 29 and connector 30 from vessel 11 withreference to the image transmitted by television camera 41 or byproviding suitable cooperating aligning means on the connector and entryconduit. Aligning means of this type is disclosed in copending US.application Ser. No. 731,382 filed May 23, 196 8. Attached to bodymember portion 45 by any suitable means, such as by welding, is an innerconduit assembly means comprising plate means 60 and tubing runs 37 and38. The assembly means further includes locking plate means 61 which issecured to plate means 60 by means of screws 62 and 63. The tubing runs37 and 38 extend through axially aligned apertures in plate means 60 andlocking plate means 61 and are fixedly secured in the positionillustrated by any suitable means. For example, the tubing runs may bewelded onto locking plate means 61 or may be press fit into theassociated apertures of locking plate means 61. Other pipe members foreffecting various well operations, such as tubing member 64, may also bedisposed in body member portion 45 and extend through plate means 60 andlocking plate means 61. The end of tubing member 64 which has not beenillustrated would be operatively connected to a suitable power sourcesuch as one of the conduits 53. Tubing runs 37 and 38 and tubing member64 preferably incorporate recessed ends 65, 66 and 67, respectively,with sealing elements disposed thereon in the manner shown. if desired,electrical cables to effect various operations on the wellhead couldalso be disposed in body member portion 45 and extend to plate means 60.Any such electrical cables would be equipped with termination fittingsof any suitable design and attached to plate 61. Since electrical cablesand connectors of any suitable type well known in the art may be used inthis purpose it is not deemed necessary to describe such an arrangementfurther.

A support plate 68 is disposed in wellhead entry conduit 28 as is alsoshown in FIG. 3. Fixedly positioned in support plate 68 by means of anyknown expedient are connector elements 69 and 70 and tubing membercoupling element 71 all of which comprise cylindrical pipes. Theconnector elements 69 and 70 extend downwardly into the wellheadassembly and are in axial alignment and fluid communication withproduction tubing strings 20 and 21. In the event electrical terminationfittings and electrical cable means are operatively associated with theplate means 61 mating electrical fittings or plugs of any suitabledesign would be provided on support plate 68 with cooperating cablemeans (not shown) extending into the assembly. During the actual wellproduction operation valve means (not shown) interrupts the fluidcommunication between tubing strings 20 and 21 and their respectiveconnector elements 69 and 70. US. Pat. No. 3,064,735 may be referred tofor a more detailed description of an arrangement of this type. Tubingmember coupling element 71 is in operative communication with one ormore valve elements, latches, etc. (not shown) within the assembly orthe well itself and which are elfective to shut down the well or performother desired operations. Alternatively, the above-described electricalcables and connectors which may be employed could be used for thispurpose. Since the precise nature of the operations to be performed varyaccording to the design of the particular wellhead assembly employed andthe exigencies of the desired operation, no attempt has been made todescribe this feature in greater detail. The connector according to thepresent invention could, of course be utilized with various numbers andsizes of pipes and/ or electrical cables as desired.

After the wellhead connector 30 has been latched into position onwellhead entry conduit 28 and the connector 30 has been rotated so thatthe body member portion 45 is aligned with respect to wellhead entryconduit 28 as shown in FIG. 3, the valve means (not shown) in conduits51 (FIG. 2) are opened thereby building up hydraulic pressure in chamber49 by flowing hydraulic fluid from accumulators 50. Rather than usingthe disclosed accumulators to provide the source of hydraulic fluid adirect operating hydraulic circuit could be established between one ofthe hydraulic conduits 53 and chamber 49 with hydraulic fluid pressurebeing furnished directly from vessel 11. By acting upon flange member 46the hydraulic pressure within chamber 49 serves to force body memberportion 45 and pipe string 29 in a downward direction so that allelements of wellhead connector 30 including tubing runs 37 and 38 andtubing member 64 are positioned as shown in FIG. 2. Body member portion45 is now in its extended second position. After the pull-down operationhas taken place, a hydraulically operated latch 72 is actuated tocooperate with a flange member 73 which is fixedly disposed about theperiphery of body member portion 45. Latch 72 serves to lock tubing runs37 and 38 and tubing member 64 into fluid-tight engagement with theirrespective cooperating connector elements 69 and 70 and tubing membercoupling element 71. In like manner, any mating electrical connectorsemployed on plate means '61 and support plate 68 would be brought intoengagement.

After the wellhead connector 30 has been connected as shown in FIG. 2,the desired operations may be performed. For example, tools orinstruments may be cir culated down the well through the tubing runs 37and 38, through connector elements 69 and 70, and into production tubingstrings 20 and 21. The procedure for circulating tools and instrumentsthrough a wellhead assembly of this type, i.e., a Y-branched wellheadassembly, is more clearly set forth in the above-noted U.S. Pat. No.3,064,- 735. If desired, suitable manipulations may be carried outthrough tubing runs 37 and 38 to close down the well and remove all or aportion of the Wellhead assembly 25 to the surface by pulling the pipestring 29 thereby permit- 7 ting suitable maintenance or otheroperations to be performed on the vessel. US Pat. No. 3,064,735 alsodescribes an arrangement for effecting the removal of a wellheadassembly to the surface of a body of water for this purpose.

While this invention has been described with particular reference to apreferred embodiment thereof it should be understood that the formillustrated herein has been selected to facilitate the disclosure of theinvention rather than to limit the number of forms which it may assume,and various modifications, adaptations and alterations may be applied tothe form shown to meet the requirements of practice without departingfrom the spirit or scope of the present invention.

I claim as my invention:

1. A wellhead connector lowerable to an underwater wellhead assembly bymeans of a pipe string extending from a vessel floating on the surfaceof a body of water, said underwater wellhead assembly including anupstanding member having fluid conduit means herein, said connectorcomprising:

a body member having a vertical throughbore and being positionable oversaid upstanding member by said pipe string;

latch means carried by at least one of said members for effectingattachment therebetween;

a portion of said body member surrounding said throughbore being mountedfor downwardly extensible axial movement with respect to the rest ofsaid body member;

inner conduit assembly means carried by said body member portion formovement from a first position to a second position;

prime mover means carried by said body member and operatively engagingsaid body member portion for moving the inner conduit assembly meansfrom said first position to said second position; and

cooperating means on said fluid conduit means of said wellhead assemblyand said inner conduit assembly means for establishing fluid-tightcommunication therebetween upon movement of said inner conduit 8assembly means from said first position to said second position;

said inner conduit assembly means comprising substantially rigid tubemeans fixedly positioned in plate means mounted at one end of said bodymember portion, said plate means having aperture means therein throughwhich the tube means protrudes.

2. The connector according to claim 1, wherein a framework extendsoutwardly from said body member, said framework carrying wellheadassembly locating means and positioning means for assisting the operatorin locating the wellhead assembly and operatively posititoning theconnector with respect to the wellhead assembly.

3. The connector according to claim 1 wherein said prime mover meanscomprises a hydraulically actuated piston operatively associated withaccumulator means mounted on said pipe string.

4. The connector according to claim 1 wherein said inner conduitassembly means is of a size to permit downward extension thereof intosaid upstanding member fluid conduit means of said wellhead assembly,said fluid conduit means being recessed downwardly from the top of saidupstanding member.

References Cited UNITED STATES PATENTS 3,052,299 9/ 1962 Geer et a1.166-.6 3,071,188 1/1963 Raulins 166.6 3,217,805 11/1965 Howard 166-.63,265,130 9/1966 Watkins 166-.6 3,301,322 1/1967 Newsome 166-.63,332,484 7/1967 Watkins 166.6 3,339,632 9/1967 Lewis 166.6 3,419,07112/1968 Williams 166-.6

NILE C. BYERS, 111., Primary Examiner R. E. FAVREAU, Assistant ExaminerU.S. C1. X.R. 285-26, 137

